Spanish past progressive
El Imperfecto Progresivo is a tense that describes actions in progress in the past.
It uses "estar" in El Imperfecto followed by a gerund.
It is used for those actions in progress in the past with a descriptive function, not giving any emphasis to the beginning or end.
Vosotros estabais decidiendo el menú de la boda.You were deciding on the wedding menu.